MCP STDIO Design Choice Enables Widespread RCE Risk
⚠️ Researchers at OX Security warn that a design decision in Anthropic’s reference Model Context Protocol (MCP) STDIO implementation may permit remote code execution (RCE) when client applications start local MCP servers without proper command filtering. The flaw stems from SDKs accepting arbitrary STDIO commands as subprocess arguments, which many adapters and tools inherit. Anthropic and other framework maintainers say this behavior is by design and that application developers must sanitize inputs, but OX found few effective defenses and demonstrated RCE across numerous projects and services.
